Typical conventional fire detectors include a fire detection system which may be an ion chamber sensitive to smoke, an optical smoke detector operable in response to the scattered light or the reduced light due to the smoke emitted from a fire, a flame sensor, a burned gas sensor, or a thermally responsive element. These fire detection systems are typically coupled to a discriminator circuit suitable for the respective type of the fire detection system. When the smoke emitted from a fire enters the fire detection system within the casing through an air passage formed therein, the fire detection system detects the smoke and the discriminator circuit generates an electrical signal representative of the presence of the smoke. This electrical signal causes an alarm device to generate an alarm signal.
It has been known to provide a visual indication device, such as a lamp energized upon the detection of a fire, in a fire detector per se such as by mounting it in the base or the casing of the detector.
In order to make sure that people around the fire detector and the alarm are warned without having to look at the alarm device, various types of commercially available standardized acoustic alarm devices are usually employed in combination with a fire detector. Such acoustic alarm devices include electromagnetic buzzers, electric bells, electric horns etc. However, such fire detectors and additional alarm devices are formed as two individual devices and separately attached to the ceiling for example of the building. When desired, they may be mounted on a common base or enclosed in a common casing. However, these common bases and casings are relatively large. Therefore, conventional fire detectors having fire detection systems and alarm devices are bulky and complex in structure.